/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.sdk.io.gcp.bigquery;



import com.google.api.services.bigquery.model.Table;

import com.google.api.services.bigquery.model.TableReference;

import com.bff.gaia.unified.sdk.coders.Coder;

import com.bff.gaia.unified.sdk.io.gcp.bigquery.BigQueryHelpers.TableRefToJson;

import com.bff.gaia.unified.sdk.options.PipelineOptions;

import com.bff.gaia.unified.sdk.options.ValueProvider;

import com.bff.gaia.unified.sdk.options.ValueProvider.NestedValueProvider;

import com.bff.gaia.unified.sdk.transforms.SerializableFunction;

import com.bff.gaia.unified.sdk.transforms.display.DisplayData;

import com.bff.gaia.unified.vendor.guava.com.google.common.annotations.VisibleForTesting;

import com.bff.gaia.unified.vendor.guava.com.google.common.base.Strings;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;



import java.io.IOException;

import java.util.concurrent.atomic.AtomicReference;



import static com.bff.gaia.unified.vendor.guava.com.google.common.base.Preconditions.checkNotNull;

import static com.bff.gaia.unified.vendor.guava.com.google.common.base.Preconditions.checkState;



/** A {@link BigQuerySourceBase} for reading BigQuery tables. */

@VisibleForTesting

class BigQueryTableSource<T> extends BigQuerySourceBase<T> {

  private static final Logger LOG = LoggerFactory.getLogger(BigQueryTableSource.class);



  static <T> BigQueryTableSource<T> create(

      String stepUuid,

      ValueProvider<TableReference> table,

      BigQueryServices bqServices,

      Coder<T> coder,

      SerializableFunction<SchemaAndRecord, T> parseFn) {

    return new BigQueryTableSource<>(stepUuid, table, bqServices, coder, parseFn);

  }



  private final ValueProvider<String> jsonTable;

  private final AtomicReference<Long> tableSizeBytes;



  private BigQueryTableSource(

      String stepUuid,

      ValueProvider<TableReference> table,

      BigQueryServices bqServices,

      Coder<T> coder,

      SerializableFunction<SchemaAndRecord, T> parseFn) {

    super(stepUuid, bqServices, coder, parseFn);

    this.jsonTable = NestedValueProvider.of(checkNotNull(table, "table"), new TableRefToJson());

    this.tableSizeBytes = new AtomicReference<>();

  }



  @Override

  protected TableReference getTableToExtract(BigQueryOptions bqOptions) throws IOException {

    TableReference tableReference =

        BigQueryIO.JSON_FACTORY.fromString(jsonTable.get(), TableReference.class);

    return setDefaultProjectIfAbsent(bqOptions, tableReference);

  }



  /**

   * Sets the {@link TableReference#projectId} of the provided table reference to the id of the

   * default project if the table reference does not have a project ID specified.

   */

  private TableReference setDefaultProjectIfAbsent(

      BigQueryOptions bqOptions, TableReference tableReference) {

    if (Strings.isNullOrEmpty(tableReference.getProjectId())) {

      checkState(

          !Strings.isNullOrEmpty(bqOptions.getProject()),

          "No project ID set in %s or %s, cannot construct a complete %s",

          TableReference.class.getSimpleName(),

          BigQueryOptions.class.getSimpleName(),

          TableReference.class.getSimpleName());

      LOG.info(

          "Project ID not set in {}. Using default project from {}.",

          TableReference.class.getSimpleName(),

          BigQueryOptions.class.getSimpleName());

      tableReference.setProjectId(bqOptions.getProject());

    }

    return tableReference;

  }



  @Override

  public synchronized long getEstimatedSizeBytes(PipelineOptions options) throws Exception {

    if (tableSizeBytes.get() == null) {

      TableReference table =

          setDefaultProjectIfAbsent(

              options.as(BigQueryOptions.class),

              BigQueryIO.JSON_FACTORY.fromString(jsonTable.get(), TableReference.class));



      Table tableRef =

          bqServices.getDatasetService(options.as(BigQueryOptions.class)).getTable(table);

      Long numBytes = tableRef.getNumBytes();

      if (tableRef.getStreamingBuffer() != null) {

        numBytes += tableRef.getStreamingBuffer().getEstimatedBytes().longValue();

      }



      tableSizeBytes.compareAndSet(null, numBytes);

    }

    return tableSizeBytes.get();

  }



  @Override

  protected void cleanupTempResource(BigQueryOptions bqOptions) throws Exception {

    // Do nothing.

  }



  @Override

  public void populateDisplayData(DisplayData.Builder builder) {

    super.populateDisplayData(builder);

    builder.add(DisplayData.item("table", jsonTable));

  }

}